Isolating ring for lamp assembly

ABSTRACT

An isolating ring for isolating a lamp from a circular rimmed housing. The isolating ring consists essentially of a resilient annular which has an internal gallery for receiving the rim of the housing. The housing rim has cutaway portions at intervals and the annulus of the isolating ring has integral lugs which extend inwardly through the cutaway portions and which bear against the lamp. Because the lugs register with the cutaway portions, and because one of the lugs is shaped to register with a protruding portion of the lamp, relative shifting between the isolating ring, the lamp and the housing is prevented. The isolating ring has an inward lip which urges the lamp against the lugs.



1. In combination, a lamp, a lamp housing having a circular rim, the rim defining the mouth of a cavity adapted to receive the lamp, the rim having four recesses spaced at 90* intervals, and an isolating ring consisting of a resilient annulus, an internal gallery in said annulus for receiving said circular rim, at least three lugs protruding inwardly from said annulus and adapted to register with said recesses when said circular rim is received within said gallery, a lip extending inwardly from said annulus for engagement with the lamp and for urging the lamp toward said cavity and against said lugs, thereby completely to isolate said lamp from direct contact with said lamp housing, said lamp having a projection adapted to register with one of the lugs, thereby to orient the lamp in one of at least three positions with respect to the isolating ring, each lug being shaped to receive said projection, whereby mutual rotation as between the lamp and the isolating ring is restrained.
 2. The invention claimed in claim 1 or claim in which there are four lugs adapted to register with the four recesses.
 3. The invention claimed in claim 1 or claim 1, in which said lugs protrude from said internal gallery.
 4. The invention claimed in claim 1, in which said circular rim includes an annular flange portion extending substantially radially outwardly from the housing and a substantially cylindrical portion extending from the periphery of said annular flange portion in the direction away from said cavity, said recesses being defined by breaks in said substantially cylindrical portion, said substantially cylindrical portion being adapted to be received in said internal gallery.
 5. The invention claimed in claim 1 or claim 1 in which the cross section of said resilient annulus taken in planes containing the axis of said resilient annulus is substantially constant, said cross section consisting of an elongated body portion of which the longer dimension is substantially parallel with said axis, the face of said elongated body portion which is adjacent said axis having a stepped indentation of which the deeper part provides the said gallery and of which the shallower part defines the inner wall of the said lip. 